Storing potatoes is important to consider when growing them, or just wanting to make the ones you buy last longer. Sometimes you can get great deals on potatoes if you buy them at harvest time or in bulk. With the correct techniques you can keep potatoes stored for a long time. We often have our spuds last from October until the following June. That is if I don’t eat them all by then.
To store potatoes, you need to keep the potatoes cool, out of light, well ventilated, and have the correct humidity.
What happens to the potato as it’s stored?
Potatoes themselves are a tuber. They are formed on the roots of the potato plants. Many people think that potatoes are a root vegetable, they are not. They are tubers that are formed on the roots during the growing life of the potato plant.
Many of the same methods used for storing root vegetables can be used with potatoes. However, you will want to keep root vegetables a little less ventilated than potatoes. Here is an article that can help you with storing root vegetables.
Potatoes are a living thing and storage is just slowing the growth process. As time goes on the potato will naturally change from starch to sugar and sprouts will grow from the eyes of the potato. When light hits the potato, it triggers this growth process as well. This can happen between 30-140 days after they are harvested. (Source)
Things to consider in potato storage.
Type of potato.
There are all kinds and types of potatoes that have been cultivated. You probably have seen them in the grocery store and seed catalogs. You may have even grown some in your own spud patch. White, red, purple, small, large, petite, bakers, fingers are all potatoes that are grown and sold. With all the different types of potatoes some will store better than others.
There are 7 basic types of potatoes and over 200 varieties with more seeming to show up every year.
The 7 basic types of potatoes are:
1-Russets- Russet potatoes are a medium to larger potato and are generally an oval or oblong shape. They are a brown color that can vary in shade from light to a medium brown. They have a light yellow or white flesh. They are excellent storage potatoes. If you grow them in your own garden, some of these potatoes become monstrous in size. One potato can feed your whole family.
2-Reds- Red potatoes are often harvested when they are small to medium and immature. They have a waxy, moist, and smooth flesh with a thin red skin. They are round or oblong in shape. However, if you grow them in your own garden you don’t have to harvest them early when they are immature. You can keep them growing and they can grow large and still keep the same characteristics as the small potato. With the proper care these potatoes will store well, but without the proper precaution they will rot, sprout, and spoil.
3-Whites- White potatoes are generally small to medium in size. They have a thin skin that looks white to light tan in color. The flesh is fairly dense and starchy. These potatoes will store well if you take the proper steps. As with most all the potatoes you can grow larger ones than typically found in the store.
4-Yellows– Yellow potatoes are anywhere from marble size to huge depending on when they are harvested. They have a light yellow/tan to golden skin. They have a waxy yellow flesh. These potatoes will store well and are becoming very popular to the home gardener and the homesteader looking for a cash crop.
5-Purple- Purple potatoes are a relatively new novel variety. They are small to medium sized round or oblong. Very distinctive with their dark purple to blue skin. The flesh is dense and firm. The flesh color can vary from pink to blue to purple. It also can vary from light to dark in color. These potatoes can also store fairly well. These varieties are often harvested when they are immature and do not store as well as if they had been harvested at maturity.
6-Fingerling- Fingerling potatoes are becoming very popular for a fun festive dish. Fingerling potatoes are small long or oblong in shape. They resemble fingers in shape, and can kind look knobby. They are all colors under the rainbow. The flesh can be red, purple, orange, white, yellow, and will sometimes have veins of color running throughout. These are heirloom potatoes and will store well depending on when you harvest them.
7-Petite- Petite potatoes are more of a size class than anything. They have been propagated from the original traditional potatoes to have a smaller size and somewhat more concentrated flavor. Most petite potatoes are potatoes that are harvested early in the season. These do not store well unless you are very careful in harvesting storage.
Most all potatoes will store well if the proper precaution is taken. However, russets, reds, and yellows have proven to be great for storing for long periods. The thicker the skins are the better they store.
Washing and handeling
Do not wash potatoes before storage. Washing can stimulate the growth process to begin. It also can thin the skin of the potato. Try not to handle and drop or bump the potatoes around when storing them. They are not as fragile as eggs, but try to be careful. Bruising and scratching or gouging can create premature rotting and spoilage.
If you find some soft potatoes while putting them into storage, or during your storage time. Take them out and discard them or put them into your compost pile. You should also separate potatoes that might have been cut during harvesting. They should be used as soon as you can, they will decompose fairly quickly.
Temperature
The temperature has a lot to do with the storage of the potato. You mainly want to keep between 42-50 degrees Fahrenheit, or 5.5-10 degrees Centigrade.
Careful consideration needs to be used when choosing a temperature. The cooler the potato is stored the longer you can store them without sprouting. The higher the temperature the more chance you will have the potato sprouting.
When you keep the potatoes stored cold it will change the starch of the potato into a sugar. If you fry these potatoes that have been stored in colder conditions, they will have a color change in the flesh when fried. The colder the potato is stored the browner the flesh will look when they are fried. You may want to consider storing your potatoes at a warmer temperature if you are going to fry them.
The colder stored potatoes remain white when boiled or baked. The flesh only turns darker and browner if they are fried. Some people even like a sweeter flavor to their baked and boiled potatoes.
Potatoes that are stored frozen need to be processed or cooked before you freeze them. Freezing a fresh raw potato will turn the flesh grey. The flavor can be affected as well as the look. It’s not recommended to freeze your raw spuds.
Storing potatoes at a warmer temperature will encourage them to sprout sooner. When the potato sprouts the potato begins to change. The potato will become soft especially around the eye of the potato. The eyes will sprout and use the potato as nutrients for the new growing plant. If the potato hasn’t sprouted too much or become too soft you can eat it just fine. The softer the potato and more sprouting the worse it tastes.
We have a couple of articles on potato sprouts on the blog. Here is one on how to keep you potatoes from sprouting, and here is one on questions that we answer about potato sprouts.
Sometimes you don’t have much of a choice with the temperature of your storage. If you do have some control or choice of the temperature of your storage you will want to consider how you will be eating your potatoes. The warmer the temperature the better the flesh for frying, the cooler the temperature the longer you will be able to store the potatoes.
Humidity
Potatoes are a living thing and are 80% water. They require humidity or moisture to store them well. If potatoes are stored too dry, they will shrivel up and wrinkle. The dryer the storage the more dehydrated potatoes get. You can still eat them if you would like or need to, but they won’t be very good table fare.
Commercial potato storage has the humidity set at around 90-95%. Not many homes are this high in humidity. If they are this high in humidity, they are usually too hot in temperature.
There are some techniques that you can use to regulate the humidity and get it higher if you need to.
- If you have a root cellar you can put trays of water in front of the potatoes.
- If you are using plastic bags or sacks you can make smaller holes for the ventilation.
- You can cover the potatoes with a damp cloth or blanket.
- You can also spray or poor water on a burlap cover or sack.
Light is also a concern.
Light is something to avoid when storing potatoes as well. Light triggers the chlorophyll in the potato to change chemically and turn green. It’s just mainly on the shin or surface of the potato.
Once the potato turns green it doesn’t turn back if you put the potato back into the dark. Once it’s happened it’s permanent. The greening of a potato doesn’t change the taste. You can cut off the green part and eat the rest of the potato.
It’s advised that you don’t eat a lot of the green part of the potato. When the chlorophyll reacts, it creates a chemical reaction in the potato. This is where there is a buildup of glycoalkaloids. The glycoalkaloids are a protein that will make the potato taste bitter. The glycoalkaloids are also toxic if you eat a too much of them. It does take quite a bit for it to be harmful. But it is something to think about for sure.
Unless you are wanting to use your potatoes for seed to grow potato plants. Potatoes need to be kept in the dark for storage. If you do want to use your potatoes for growing new plants read this article here and it will let you know all the ins and outs of growing potatoes.
Methods of potato storage
There are a few options for potato storage. The main things to think about are the temperature, humidity, and light. Other things to consider would be the convenience and cost of your storage.
Dirt floor cellars are great for storing potatoes. This is my personal preference. Using sandy soil to line the bed of your potato pit in the cellar is recommended. This will allow for better ventilation and humidity control.
If you don’t have a cellar there are some other techniques for increasing the humidity of the stored potatoes.
A refrigerator set a higher temperature works well. I have seen a lot of smaller refrigerators available for a pretty reasonable price. You can also find some used refrigerators that might work for reasonable storage for your potatoes. You would be able to store most other root vegetables in there as well.
You can use a plastic bag or sack. This will allow you to keep the humidity higher. You will need to put some slits in the side to allow for ventilation. If there is no ventilation you will kill the potatoes and they will rot. This may take some trial and error to figure out how many cuts in the plastic bag, but it works.
Cardboard boxes and paper sacks can work well. Many potatoes are sold and transported in cardboard boxes and paper sacks. These can often work well in regulating the humidity of your potatoes.
Burlap sacks have been a great option for potato storage for decades. Burlap is cheap and has good ventilation. Burlap can be useful with maintaining humidity as well. You can spray or pour water on the burlap sacks to keep the moisture higher as needed. Burlap will break down as time goes on, but it is a great proven method of potato storage.
Bins are also an option. Depending on how many potatoes you need to store and your storage space you can find a bin that will probably fit. You just need to remember to have ventilation and be able to keep it in the dark. Some bins that could be used are a laundry basket, milk crate, industrial storage bin, plastic bucket with holes drilled, just to name a few.
You can also repurpose things to create potato storage. Many containers can be found at a secondhand store, good will, freecycle, craigslist, etc. With minimal to no coast you could repurpose a chest of drawers, an old cooler, a cupboard, for some ideas. The main thing is to remember that you need ventilation,
How long can you store potatoes?
The question always comes up. How long can we actually store potatoes? When you take the proper precautions, you can store potatoes for months. At our place we use a root cellar for storage. We harvest our spuds in October and are eating them all through the winter and spring into May and sometimes June if they aren’t all consumed by then. That’s over 7 months. Commercial growers can keep potatoes in a dormant state for even longer.
Main points to consider in storing potatoes.
The main things to consider in potato storage are:
- The type of potato Thicker skinned potatoes store longer
- The temperature of the storage area The temperature needs to be between 42-50 degrees Fahrenheit, or 5.5-10 degrees Centigrade.
- The humidity of the storage area The humidity needs to be as close to 90-95% as you can
- The lightfastness of the storage area The potatoes need to be stored in the dark, or they will turn green and sprout.